My mother, who was a French major in college, learned a lot more about the French language than I ever did. She once told me that a circumflex is often indicative of an S having been removed from the word at some point in its history (the circumflex is the little “hat” that the French sometimes put on top of their vowels (â, ê, î, ô, and û.). Why the French felt the need to memorialize the lost letter permanently is beyond me, but it’s interesting and sometimes helpful.
My favorite example is “la fenêtre,” the French word for “window.” If you add an S after the circumflexed letter, you get “fenestre.” Then you can see a clear link between it and the English word “defenestration.” (My kids think the word “defenestration” is hilarious, BTW, right on par with “exsanguination,” which is another word with a French connection–“le sang” means “blood” in French.)
Knowing that a French word might have once contained an S can sometimes be helpful when trying to figure out its meaning. For example, the other day I came across the verb “hâter.” Always looking for cognates, I naturally guessed “to hate,” but that didn’t fit the context, so I tried adding an S (“haster”), et voila! The meaning was revealed. It means “to hasten.” Similarly, “la hâte” means “haste,” “hâtif” means “hasty,” and “hâtivement” means “hastily.” Now I will be able to remember the meaning of “hâter,” because all I need for remembering a French word is something to hang my hat on, and in this case it’s the “hat” itself!